The SpaceX rocket used for the ill-fated Zuma mission to fly again today

Enlarge / A sooty Falcon 9 rocket is ready for launch at Vandenberg Air Force Base in California. (credit: NASA)

SpaceX will attempt its 10th launch of the year on Tuesday, a mission serving two different customers. The Falcon 9 rocket will carry five communications satellites for the Iridium NEXT constellation, along with two gravity-measuring satellites for NASA and the German Research Centre for Geosciences.

This first-stage booster has flown once before, a little more than four months ago when it launched the Zuma mission for the US government-a satellite or spacecraft that was apparently lost in space after it failed to separate from the second stage of the Falcon 9 rocket. SpaceX appears to have been absolved from blame for this mishap, and certainly the first stage booster performed nominally during that mission.

SpaceX will not attempt to recover this core, as it is a Block 4 variant of the booster. Each Block 4 core will fly just two times as the company seeks to move all of its launches onto the newer Block 5 version of the rocket, which has slightly increased performance and numerous upgrades to optimize the first stage for reusability.

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